Car says cold

Hello all,

I am around Baltimore and for the last week we have been in the teens for temperatures outside. My 02' WS6 won't heat up/stay heated up with moderate speed driving. I've been keeping it in a lower gear than I should to up the temp (the gage shows its at the left 45 degree marker on the instrument panel). It's not just the gage that makes me thing this, the heater in the car isn't blowing as warm as I think it should. Theres coolant showing still on the coolant dipstick too. I presume its thermostat, but the weird thing is that I haven't thrown a P0128 code (or at least no SES lighs have tripped), which I hear is typical when an OBDII 'stat is stuck open.

Is it normal for these cars to stay this cold in these temps? (never been this cold for this long around here) Any other ideas?

Check the thermostat first, would be my best guess

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Originally Posted by tatertot91

Check the thermostat first, would be my best guess

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That's what I have been thinking too. Last night and this morning it warmed up and was fine, but it was near freezing today. It seems that the problem is when it dips to the low teens or colder.

I've been hearing that factory Tstats stick closed, not open, is this true? As far as I know, this is the original T-stat, I bought the car in January '07, but the only mod that seemed to have been done on the car was a CAGS Skip Shift Eliminator, so I don't think it has an aftermarket (lower opening temperature) 'stat.

My question hasn't been as much a diagnosis, as is it also asking how these cars do at near 0' F. Now that it has gotten back to the 32' F range here, the operating temperature is fine. Do you guys in the frigid (or even "Great White") North have problems keeping the car in normal range when it hits 0'?

I am not sure, but it makes sense to me that the engine would run a lot colder in cold weather...just like it runs a lot warmer in hot weather. The outside elements do play a big factor on what temperature an engine operates at. I really don't see it being an issue.

That makes sense to me too. I just remember my iron block/headed SBC and Old's V-8 were able to stay warm in really cold temp's. Probably because iron holds heat better than aluminum does. It just freaked me out a tad.

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Originally Posted by tatertot91

Check the thermostat first, would be my best guess

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+2 on this, it maybe stuck in the open position.

After second thought, I'm with these guys. We've had a subzero winter here and all my cars stay around the 1/4 mark on the temperature gauge.

I plan on checking the stat as soon as I have a chance, but its really to cold for me to do it myself right now, I live in a townhome so no garage for me. If it was critical enough I'd drop it off at the shop.But the odd thing is now that since we have been at more reasonable temperatures (30-ish F) the temperature is fine. It was just that week when we were constantly at 10' or so. It would fight to stay near the 1/4 mark. I would figure that if the stat was stuck open, I would still be having these problems, would I not?

I don't think anyone has stated this -- but the stock temp gauge in our cars (excluding '98s) are estimators at best. Do NOT reply on the gauge reading as being accurate. Our gauge reads 205 degrees all the time - when actual temp may only be in the mid-180's. That being said, I agree that it sounds like you have a stuck open thermostat.

My car is a blast furnace during the winter. I keep the heater set to half as if I have it set to max, I get burned. I also agree with thecking the t-stat. Question, are you running a lower temp t-stat?

Any t-stat can fail, OE or not, and they can fail stuck closed, stuck open, or they can open too soon or not enough.

Sounds like OP has a t-stat that is opening too soon, and it really shows up on very cold days.

I do not believe that the thermostat is a lower temp. When I bout the car in Jan' 2007 the only thing that didn't appear stock on the car was a skip-shift eliminator. I would be surprised if it had one. I will check the Tstat as soon as I can. I am not driving much right now, just graduated college and trying to get a job.

Get back to us with what you find. If it isn't the tstat, we can help you narrow things down and find the culprit.

Thanks, I appreciate it. I just got a job offer and should be starting before the end of the month. By then, it will either be:

1) Warm enough to check it myself (the 'bird is under almost two feet of snow right now, with more on the way tonight :( )

2) Drop it off to a shop after I get my first check.

For all I know, this could be why I am not breaking 19 mpg average, when I used to get about 26-ish

Testing the thermostat is simple. First, remove it from the car and examine it to see if it appears to be stuck open. You should see markings on the thermostat that will indicate the temp it should be fully open. Usually this will be 185. But if it was replaced with an aftermarket it might be as low as 160. If it does not appear to be stuck in the open position, put it in a pot of water on your stove and begin heating it up. Have a thermometer in the pot to watch the water temperature to see when the thermostat begins to open. It should be fully open by the temperature marked on the part. If not, you can at least see what temp it is fully open at or if it opens fully at all. Our collective guess is when you remove yours you will find it stuck in the open position which will prevent your engine from building heat at lower temperatures. Good luck!

I understand how to test it, its the sub-freezing temperatures that I would be working in that are the problem for me. I don't have access to a garage to work in at the moment.

I would avise wait until the temps improve. I work outside and I will say it's not for everyone.

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Originally Posted by sjgreen6

Testing the thermostat is simple. First, remove it from the car and examine it to see if it appears to be stuck open. You should see markings on the thermostat that will indicate the temp it should be fully open. Usually this will be 185. But if it was replaced with an aftermarket it might be as low as 160. If it does not appear to be stuck in the open position, put it in a pot of water on your stove and begin heating it up. Have a thermometer in the pot to watch the water temperature to see when the thermostat begins to open. It should be fully open by the temperature marked on the part. If not, you can at least see what temp it is fully open at or if it opens fully at all. Our collective guess is when you remove yours you will find it stuck in the open position which will prevent your engine from building heat at lower temperatures. Good luck!

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One minor correction:

The marked temp on the thermostat is the temp at which it begins to open, not when it is fully open. Fully open is usually 10 or so degrees higher.

^^ Really depends on the thermostat -- only way to know for certain is to test it in boiling water with a thermometer.